I. Field of the Invention
The present invention relates generally to finishing machines for bridges. More particularly, the present invention relates to an universal vibration system for a bridge deck finishing machine. Known prior art may be found in U.S. Class 404, subclass 16 and the other various subclasses listed thereunder.
II. Description of the Prior Art
It is well-known that plastic concrete should be vibrated to densify and consolidate it during finishing to produce desirable results. The prior art includes a wide variety of vibration devices for settling and densifying plastic concrete. Several of these devices have been used with bridge decks to vibrate the plastic concrete thereon. Most of these bridge deck devices can be grouped as either single portable vibrators or truss-mounted gangs of multiple vibrators.
The portable vibrators permit an operator to vibrate a small area of concrete prior-to other finishing operations. The portable units generally comprise a power supply coupled to an elongated flexible pendulous vibrator. The operator generally transports the power unit on their back while thrusting the vibrator into the concrete. Unfortunately, these units require several operators to effectively vibrate large sectors of concrete. Also, they require experienced operators if the results are to be satisfactorily uniform. This lack of uniformity is undesirable because it often leads to sections of unconsolidated or otherwise weakened concrete. Consequently, automatic gangs of vibrators are often specified to be employed with large concrete pours to ensure satisfactory uniformity.
Several known prior art devices have been proposed to satisfy the need for an efficient bridge deck vibrating system. For example, a company named Bid-Well located in Canton, S. Dak., produces different types of bridge deck trusses. However, most of their vibrating gangs require specialized bridge deck trusses that are unduly complicated to employ for a number of reasons discussed hereinafter. One recently introduced machine mounts on the front of their proprietary bridge deck truss to alleviate some of the problems with their other specialized vibrating trusses. However, this machine does not readily retrofit other, non-proprietary bridge deck trusses commonly employed in the construction industry. Moreover, it is not a stand alone unit in that it requires a sizable remote power supply with accompanying cumbersome transfer cabling and constant operator supervision. It also exerts torsion on the truss that could adversely affect finishing operations.
It is believed that Bid-Well (or a related corporation named CMI located in Oklahoma City, Okla.) owns several patents of general relevance to the present invention. These patents include U.S. Pat. Nos. 3,738,763, 3,593,627, 4,484,834, 5,492,432, 4,256,415, 4,320,987, 4,708,520 and 4,775,262.
Other known relevant art includes U.S. Pat. No. 4,128,359. This patent shows a self-propelled concrete vibrator apparatus which includes a plurality of hydraulically powered vibrators positioned at evenly spaced apart intervals across the full width of a support truss. This device includes a plurality of hydraulic rams which raise and lower the plurality of vibrator units into and out of a mass of wet concrete. A second group of horizontally oriented hydraulic rams is coupled to the plurality of vibrator units and laterally displaces the vibrator units between a first and a second position. This device includes a hydraulic pump driven by an internal combustion engine and a plurality of four drive units for longitudinally translating the entire structure along the length of the concrete to be vibrated.
U.S. Pat. No. 2,223,734 discloses a concrete vibrator which is longitudinally translatable along the length of an area of wet concrete. This device includes a vibrator carriage that is longitudinally translatable between a first and a second position. The carriage also includes a centrally mounted shaft that permits it to pivot and thereby partially elevate the mechanically driven concrete vibrators with respect to the surface of the wet concrete.
U.S. Pat. No. 2,248,103 discloses an attachment for a screed which includes a laterally oriented frame having a plurality of evenly spaced apart vibrators. A and actuated lever permits an operator to simultaneously raise or lower all of the vibrators with respect to the surface of the wet concrete.
U.S. Pat. No. 2,382,096 discloses a paving machine having a plurality of vibrator units mounted at fixed positions laterally across the face of the device. The vibrators span the entire width of the wet concrete surface to be vibrated. This device includes a concrete screed and it is hydraulically powered. The plurality of vibrators are pivoted about a point and inserted at an angle into the wet concrete in a manner that permits the vibrators to travel beneath the concrete screed.
U.S. Pat. No. 2,292,733 discloses a concrete vibrating device including a plurality of vibrators mounted at a fixed position along the entire width of the device. The vibrators are flexibly coupled to the frame, thus permitting them to be deflected to the rear of the frame as it advances through the concrete.
U.S. Pat. No. 2,461,500 discloses and apparatus for compacting concrete slabs that includes a plurality of vibrator units mounted at fixed positions laterally across the device. Each vibrator is driven by a motor coupled to a flexible shaft. The vibrators trail behind and penetrate below the surface of the wet concrete as the device advances through the concrete.
U.S. Pat. No. 2,148,214 discloses a vibrating machine that includes an inverted "T"-shaped horizontally oriented vibrating tube that is immersed into the wet concrete. U.S. Pat. No. 2,233,833 discloses a related device having three horizontally oriented vibrating tubes that vibrate the wet concrete. A screed is also used to level the surface of the wet concrete.
U.S. Pat. No. 3,555,983 discloses a paving grout control device that includes vibrator units positioned at evenly spaced intervals laterally across the front of the device. This device includes a comb-like structure that is immersed at a point behind the vibrating units at a predetermined depth into the paving material.
U.S. Pat. No. 3,113,494 discloses a machine for finishing concrete surfaces that includes a mechanically vibrated screed. This device is laterally translated by a pair of manually operated winches, one of which is coupled to each end of the frame.
Other known patents of lesser relevance include U.S. Pat. Nos. 1,747,555, 2,030,315, 1,898,158, 3,413,902, 3,042,386, 3,180,625, 3,188,054, 2,261,659, 2,380,435, 2,583,108, 3,110,234, 3,377,933, 3,753,621, 3,299,786, 3,450,011 and 3,541,931.
Other patents owned by the assignee of this invention include U.S. Pat. Nos. 5,108,220, 5,480,257, 5,480,258, 4,577,993, 4,249,327, 4572,704 and 4,314,773, as well as others. Of the former, U.S. Pat. Nos. 4,572,704 and 4,314,773 are the most relevant to the present invention and their disclosures are hereby expressly incorporated by reference herein. They both discloses bridge deck machines that are capable of vibrating plastic concrete with gang vibrators. However, they may not be easily retrofitted to other conventional bridge deck trusses nor can they be used as stand alone vibratory gangs.
The known prior art fails to adequately address the need for all easily retrofittable gang vibration system for conventional bridge deck trusses. A conventional truss comprises several independent sections that are typically coupled together at the construction site. Since the sections are commonly available in 8, 10 and 12 foot lengths, the overall width of a particular truss may thus be adapted to satisfy varying operational parameters.
The conventional truss also employs a pair of spaced apart end stanchions that support it above the bridge or other work area. Generally, the stanchions are coupled to the exterior truss sections and they are nominally equipped with motorized wheels that move the truss. Normally, the wheels ride on a pair of spaced apart tubes that typically bound the construction site longitudinally. Thus, as the truss traverses the tubes, work is performed on the area underneath and adjacent to the truss.
However, the known prior art devices generally require specialized unitary bridge deck trusses that cannot be assembled on site in appropriate lengths to satisfy varying operational parameters. As such, they are generally undesirable. These devices also lack adaptability and they typically demand excessive prior planning to ensure their availability and workability at the Construction site. Furthermore, they also cause logistical problems that are difficult to resolve.
An improved vibration system should be installable on a conventional bridge deck truss with minimal truss alteration. Preferably, the system should be self sufficient and it should be able to operationally stand-alone without needing truss supplied power. A particularly desirable system would have guidance and location controls that enabled it to operate with minimal operator supervision or direction.